Apparatus for harvesting agricultural row crops

ABSTRACT

An apparatus for harvesting agricultural row crops having stalks, comprising a frame having a front portion and a rear portion, the frame configured for traversing along a field of row crops; a hollow arm mounted adjacent an upper section of the front portion of the frame, the hollow arm comprising a first section disposed along an incline formed by the upper section of the front portion of the frame and the ground, the first section having a first end and a second end; an inlet positioned adjacent the first end of the first section of the hollow arm, the inlet for receiving stalks of row crops; means for cutting stalks of row crops, the means for cutting stalks mounted within the first section of the hollow arm; means for engaging and conveying the stalks along the hollow arm; and a biased guide assembly for accommodating stalks of varied diameters.

This application claims priority to U.S. Provisional Application No.61/498,398, filed on Jun. 17, 2011, the contents of which are herebyincorporated by reference in their entirety.

FIELD

The present invention generally relates to an apparatus for theharvesting of agricultural row crops, and more particularly to tobaccoharvesters for cutting rows of tobacco and conveying the severed plants.

ENVIRONMENT

Many row crops, such as tobacco, require delicate handling duringharvesting to prevent damage to the leaves. As such, manual harvestingof tobacco has been employed for centuries. However, this is not onlycostly, but time consuming.

Burley tobacco is often harvested by cutting the entire stalk and curingthe leaves while attached to the stalk. The cut tobacco plants are oftenallowed to wilt in the sun for a day or so to reduce the amount ofbruising and breaking of the tobacco leaves as the plant is handled.Then, the plants are speared with a stick and hung in a curing or dryingbarn.

Attempts have been made to develop automated or semi-automatedharvesting machinery. An early manually operated tobacco harvestingmachine is the subject of U.S. Pat. No. 2,497,845, which utilized ahorizontal cutting disc or circular saw mounted for rotation about avertical axis and driven by one of a pair of wheels which contact theearth. By pushing the machine, the wheel drives the saw such that theteeth on the periphery of the circular saw sever in sequence the stalksof the tobacco plants just above the ground. The stalk is guided to thesaw for contact with the teeth periphery through laterally opposed,curved guide blades which define a throat or passage to that cuttingmember. The guide mechanism effects the subsequent disposition of thesevered plants to the side of the tobacco harvesting machine as itpasses manually down the row.

Despite advances in the art, there is still a need for a tobaccoharvesting machine which is capable of cutting tobacco stalks just abovethe ground and laying the several stalks in a common direction tofacilitate subsequent pick-up with minimal damage to the leaves of thesevered stalks.

SUMMARY

Provided herewith is an apparatus for harvesting agricultural row cropshaving stalks. The apparatus includes a frame having a front portion anda rear portion, the frame configured for traversing along a field of rowcrops; a hollow arm mounted adjacent an upper section of the frontportion of the frame, the hollow arm comprising a first section disposedalong an incline formed by the upper section of the front portion of theframe and the ground, the first section having a first end and a secondend; a stalk inlet positioned adjacent the first end of the firstsection of the hollow arm, the stalk inlet for receiving stalks of rowcrops; means for cutting stalks of row crops, the means for cuttingstalks mounted within the first section of the hollow arm; means forengaging and conveying the stalks along the hollow arm; and a biasedguide assembly for accommodating stalks of varied diameters, the biasedguide assembly comprising a plurality of individual biasing memberspositioned along at least a portion of the hollow arm to apply anaccommodating clamping force to the stalks sufficient to keep each stalksubstantially upright as they are conveyed along at least a portion ofthe hollow arm, the accommodating clamping force accommodating possibledifferences in stalk diameters from one stalk to another.

In one form, the means for engaging and conveying the stalks along saidhollow arm comprises an endless chain having a plurality of links, saidplurality of links alternately provided with at least one barb forengaging a stalk.

In another form the plurality of links are alternately provided withthree barbs for engaging a stalk.

In yet another form, the endless chain is positioned to travel along atleast a portion of a vertical wall of said hollow arm in a spacedrelationship with said biased guide assembly.

In a further form, the inlet is provided in front of said means forcutting stalks and configured to direct the row crops into said meansfor cutting stalks.

In a still further form, the means for cutting stalks includes acircular saw.

In a yet still further form, the circular saw includes a high speed toolsteel blade. In another form, the circular saw includes a carbide-tippedblade.

In yet another form, at least a portion of the individual biasingmembers include a friction-reducing polymeric coating. In still yetanother form, the friction-reducing polymeric coating includes ultrahigh molecular weight polyethylene.

In one form, each of said plurality of individual biasing members ispositioned so as to overlap with an adjacent biasing member to maintaina substantially constant compressive force on the stalk.

In another form, the biased guide assembly is effective to accommodatestalks of diameters between about 1.5 to 3.0 inches.

In yet another form, the hollow arm further includes a second sectionhaving a first end and a second end, said first end operably connectedto said second end of said first section, said second section mountedalong said upper section of said front portion of said frame.

In another aspect, provided is a method of harvesting agricultural rowcrops having stalks is provided. The method includes the steps ofsequentially engaging stalks of row crops, cutting each sequentiallyengaged stalk so as to sever each stalk from the ground, applying aclamping force to each of the engaged stalks sufficient to keep eachstalk upright and conveying the stalks to a point for collection. Theclamping force is applied by a biased guide assembly for accommodatingstalks of varied diameters, the biased guide assembly comprising aplurality of individual biasing members positioned along at least aportion of a hollow arm to apply an accommodating clamping force to thestalks as they are conveyed along at least a portion of the hollow arm,the accommodating clamping force accommodating possible differences instalk diameters from one stalk to another.

BRIEF DESCRIPTION OF THE DRAWINGS

The forms disclosed herein are illustrated by way of example, and not byway of limitation, in the figures of the accompanying drawings and inwhich like reference numerals refer to similar elements and in which:

FIG. 1 presents a front plan view of an apparatus for harvestingagricultural row crops having stalks, in accordance herewith;

FIG. 2 presents a simplified top plan view of an apparatus forharvesting agricultural row crops having stalks, illustrating the stalkcutter and gripper mechanisms;

FIG. 3 presents a partial view of FIG. 2 showing a stalk gripped by thegripper mechanism, in accordance herewith;

FIG. 4 presents a sectional view of the apparatus for harvestingagricultural row crops having stalks, taken along line 4-4 of FIG. 2, inaccordance herewith, in accordance herewith;

FIG. 5 presents a simplified perspective view of an apparatus forharvesting agricultural row crops having stalks, illustrating a stalkinlet for receiving stalks of row crops, in accordance herewith;

FIG. 6 presents a simplified perspective view of an apparatus forharvesting agricultural row crops having stalks, in accordance herewith;and

FIG. 7 presents a simplified perspective view of an apparatus forharvesting agricultural row crops having stalks, in accordance herewith;and

FIG. 8 presents a perspective view of another form of an apparatus forharvesting agricultural row crops having stalks, in accordance herewith.

DETAILED DESCRIPTION

Various aspects will now be described with reference to specific formsselected for purposes of illustration. It will be appreciated that thespirit and scope of the apparatus, system and methods disclosed hereinare not limited to the selected forms. Moreover, it is to be noted thatthe figures provided herein are not drawn to any particular proportionor scale, and that many variations can be made to the illustrated forms.Reference is now made to FIGS. 1-8, wherein like numerals are used todesignate like elements throughout.

Each of the following terms written in singular grammatical form: “a,”“an,” and “the,” as used herein, may also refer to, and encompass, aplurality of the stated entity or object, unless otherwise specificallydefined or stated herein, or, unless the context clearly dictatesotherwise. For example, the phrases “a device,” “an assembly,” “amechanism,” “a component,” and “an element,” as used herein, may alsorefer to, and encompass, a plurality of devices, a plurality ofassemblies, a plurality of mechanisms, a plurality of components, and aplurality of elements, respectively.

Each of the following terms: “includes,” “including,” “has,” “having,”“comprises,” and “comprising,” and, their linguistic or grammaticalvariants, derivatives, and/or conjugates, as used herein, means“including, but not limited to.”

By “endless chain” is meant a chain whose ends have been united by alink.

Throughout the illustrative description, the examples, and the appendedclaims, a numerical value of a parameter, feature, object, or dimension,may be stated or described in terms of a numerical range format. It isto be fully understood that the stated numerical range format isprovided for illustrating implementation of the forms disclosed herein,and is not to be understood or construed as inflexibly limiting thescope of the forms disclosed herein.

Moreover, for stating or describing a numerical range, the phrase “in arange of between about a first numerical value and about a secondnumerical value,” is considered equivalent to, and means the same as,the phrase “in a range of from about a first numerical value to about asecond numerical value,” and, thus, the two equivalently meaning phrasesmay be used interchangeably.

It is to be understood that the various forms disclosed herein are notlimited in their application to the details of the order or sequence,and number, of steps or procedures, and sub-steps or sub-procedures, ofoperation or implementation of forms of the method or to the details oftype, composition, construction, arrangement, order and number of thesystem, system sub-units, devices, assemblies, sub-assemblies,mechanisms, structures, components, elements, and configurations, and,peripheral equipment, utilities, accessories, and materials of forms ofthe system, set forth in the following illustrative description,accompanying drawings, and examples, unless otherwise specificallystated herein. The apparatus, systems and methods disclosed herein canbe practiced or implemented according to various other alternative formsand in various other alternative ways.

It is also to be understood that all technical and scientific words,terms, and/or phrases, used herein throughout the present disclosurehave either the identical or similar meaning as commonly understood byone of ordinary skill in the art, unless otherwise specifically definedor stated herein. Phraseology, terminology, and, notation, employedherein throughout the present disclosure are for the purpose ofdescription and should not be regarded as limiting.

FIG. 1 presents a front plan view of an apparatus for harvestingagricultural row crops having stalks 10, in accordance herewith. Asshown, the apparatus for harvesting agricultural row crops having stalks10 includes a frame 12 having a front portion 14 and a rear portion 16,the frame 12 configured for traversing along a field of row crops (notshown).

Apparatus 10 also includes a hollow arm 18 mounted adjacent an uppersection 20 of the front portion 14 of the frame 12. Hollow arm 18includes a first section 22 disposed along an incline formed by uppersection 20 of front portion 14 of frame 12 and the ground G, firstsection 22 having a first end 24 and a second end 26. Front portion 14of frame 12 is provided with tractor mounting points 56 for pullingapparatus through a field during a harvesting operation.

To receive stalks of row crops, hollow arm 18 of apparatus 10 isprovided with a stalk inlet 28 positioned adjacent first end 24 of firstsection 22 of hollow arm 18. To sever the stalks of row crops, hollowarm 18 also includes means for cutting stalks 30. In one form and asshown in FIG. 1, means for cutting stalks 30 may be mounted within firstsection 22 of hollow arm 18. Once severed, the stalks S are engaged andconveyed along hollow arm 18 using means for engaging and conveyingstalks 32.

In one form, means for engaging and conveying 34 may be motor driven soas by a power take-off (PTO) or an electric or gasoline or diesel-fueledmotor. The power required by the means for engaging and conveying 34 ison the order of from about one to about five horsepower.

In one form, to accommodate stalks S of varied diameters, a biased guideassembly 34 is provided. As shown in FIGS. 5-7, biased guide assembly 34includes a plurality of individual biasing members 36 positioned alongat least a portion of hollow arm 18 to a apply clamping force to thestalks S sufficient to keep each stalk S substantially upright as theyare conveyed along at least a portion of the hollow arm 18.

Biasing members 36 may be of the J-spring type shown in FIG. 5. TheJ-spring biasing members 36 are capable of a range of deflection,typically from about 0.1 to about 0.7 inches. Within that range ofdeflections, a spring force ranging from about 10 to about 30 pounds, orabout 15 to about 20 pounds, may be generated. In one form, J-springbiasing members 36 are formed from stainless steel spring stock.

Advantageously, the plurality of J-spring biasing members 36 arepreferably sized so as to provide independent biasing action againsteach stalk as a procession of stalks are moved along the arm 18 via thebarbed chain 38. Such arrangement accommodates differences in stalkdiameters from one stalk to the next, so that the conveyance of a stalkof large diameter does not compromise retention and conveyance along thearm 18 of a stalk of smaller diameter which might follow or precede thelarger one. The operative extent or width of each biasing member is afunction of typical spacing between each plant in the field and thetypical speeds at which the harvester is moved along a row of plantsduring harvesting operations. For Burley tobacco, the J-spring biasingmembers 36 may have a width of several inches, preferably, in the rangeof approximately 3 to approximately 5 inches, which is measured in thedirection of travel of the barbed endless chain up the arm 16.

J-spring biasing members 36 may be selected to be a width that is smallenough, so as not to be affected by the in-row spacing of tobaccoplants, but wide enough to exert the desired spring force of about 15 toabout 20 pounds. In one form, for Burley tobacco, where the smallesttypical in-row spacing for tobacco planting is often about 16 inches, itwas found that it was desirable to have at least one unused J-springbiasing member 36 separating each stalk S. This equates to four J-springbiasing members 36 per 16 inch segment. In other words, for Burleytobacco, a four inch wide J-spring biasing members 36 may be desirable.

Referring in particular to FIGS. 1-4, in one form, means for engagingand conveying stalks 32 along hollow arm 18 includes an endless chain 38having a plurality of links 40, the plurality of links 40 alternatelyprovided with at least one barb 42 for engaging a stalk S. As shown inFIGS. 2-4, in one form, the plurality of links 40 are alternatelyprovided with at least three barbs 42, each mounted to a platform 44 forengaging a stalk S. As shown, endless chain 38 may be positioned totravel along at least a portion of a vertical wall 46 of hollow arm 18in a spaced relationship with biased guide assembly 34.

Referring now to FIGS. 5 and 6, in one form, inlet 28 is provided infront of means for cutting stalks 30 and configured to direct the rowcrops into means for cutting stalks for severing from the roots of therow crops. While a variety of means for cutting stalks 30 arecontemplated as having utility herein, in one form, means for cuttingstalks includes a circular saw 50 mounted to hollow arm 18.

In one form, circular saw 50 includes a high speed tool steel blade. Inanother form contemplated herein, circular saw 50 includes acarbide-tipped blade. As may be appreciated by those skilled in the art,such circular saw blades are available commercially from a variety ofsources.

Referring now to FIG. 7, in one form, to aid in the smooth conveying ofstalks S of varied diameters, at least a portion of the plurality ofindividual biasing members 36 of biased guide assembly 34 are providedwith a friction-reducing polymeric coating 52. In one form, thefriction-reducing polymeric coating 52 includes ultra high molecularweight polyethylene (UHMWPE). In one form, polymeric coating 52 maycomprise an elongated strip of UHMWPE. The UHMWPE strip 52 can be ofthickness of from about 1/16 to about ¼ inch. In one form the UHMWPEstrip 52 is about ⅛ inch in thickness.

In one form, each of the plurality of individual biasing members 36 arepositioned so as to overlap with an adjacent biasing member 36 tomaintain a substantially constant compressive force on the stalk.

In one form, biased guide assembly 34 is effective to accommodate stalksof diameters between about 1.5 to 3.0 inches.

Referring now to FIG. 1, hollow arm 18 of apparatus 10 further includesa second section having a first end and a second end, the first endoperably connected to the second end of the first section, the secondsection mounted along the upper section of the front portion of theframe.

Referring now to FIG. 8, another form of an apparatus for harvestingagricultural row crops having stalks 100 is shown. As shown, theapparatus for harvesting agricultural row crops having stalks 100includes a frame 112 having a front portion 114 and a rear portion 116,the frame 112 configured for traversing along a field of row crops (notshown). Front portion 14 of frame 12 is provided with tractor mountingpoints 56 for pulling apparatus through a field during a harvestingoperation.

Apparatus 100 also includes a hollow arm 118 mounted adjacent an uppersection 120 of the front portion 114 of the frame 112. Hollow arm 118includes a first section 122 disposed along an incline formed by uppersection 120 of front portion 114 of frame 112 and the ground G, firstsection 122 having a first end 124 and a second end 126.

To receive stalks of row crops, hollow arm 118 of apparatus 100 isprovided with a stalk inlet 128 positioned adjacent first end 124 offirst section 122 of hollow arm 118. To sever the stalks of row crops,hollow arm 118 also includes means for cutting stalks 130. In one formand as shown in FIG. 8, means for cutting stalks 130 may be mountedwithin first section 122 of hollow arm 118. Once severed, the stalks areengaged and conveyed along hollow arm 118 using means for engaging andconveying stalks 132.

As indicated above, means for engaging and conveying 134 may be motordriven so as by a power take-off (PTO) or an electric or gasoline ordiesel-fueled motor. The power required by the means for engaging andconveying 134 is on the order of from about one to about fivehorsepower.

In one form, second end 126 includes a ballast 158 so that hollow arm118 can easily rise or drop according to the irregularities of theground G. Hollow arm 118 may advantageously be mounted so as to be ableto swivel around both vertical axis and a horizontal axis.

In one form, to accommodate stalks of varied diameters, a biased guideassembly 134 is provided. Biased guide assembly 134 includes a pluralityof individual biasing members 136 positioned along at least a portion ofhollow arm 118 to a apply clamping force to the stalks S sufficient tokeep each stalk substantially upright as they are conveyed along atleast a portion of the hollow arm 118.

Biasing members 136 may be of the J-spring type shown in FIG. 5. TheJ-spring biasing members 136 are capable of a range of deflection,typically from about 0.1 to about 0.7 inches. Within that range ofdeflections, a spring ranging from about 10 to about 30 pounds may begenerated. In one form, J-spring biasing members 136 are formed fromstainless steel spring stock.

Still referring to FIG. 8, as with the form depicted by FIGS. 1-4, meansfor engaging and conveying stalks 132 along hollow arm 118 includes anendless chain (not shown) having a plurality of links, the plurality oflinks alternately provided with at least one barb (not shown) forengaging a stalk.

Consistent with the form shown in FIGS. 2-4, the plurality of links arealternately provided with at least three barbs, each mounted to aplatform for engaging a stalk. An endless chain may be positioned totravel along at least a portion of a vertical wall 146 of hollow arm 118in a spaced relationship with biased guide assembly 134.

Referring again to FIG. 8, in one form, inlet 128 is provided in frontof means for cutting stalks 130 and configured to direct the row cropsinto means for cutting stalks 130 for severing from the roots of the rowcrops. While a variety of means for cutting stalks 130 are contemplatedas having utility herein, in one form, means for cutting stalks includesa circular saw (not shown) mounted to hollow arm 118.

As indicated above, the circular saw may include a high speed tool steelblade. In another form, the circular saw may include a carbide-tippedblade. As indicated, such circular saw blades are available commerciallyfrom a variety of sources.

As with the form depicted in FIG. 7, to aid in the smooth conveying ofstalks of varied diameters, at least a portion of the plurality ofindividual biasing members 136 of biased guide assembly 134 are providedwith a friction-reducing polymeric coating. In one form, thefriction-reducing polymeric coating 152 includes ultra high molecularweight polyethylene (UHMWPE). In one form, polymeric coating 152 maycomprise an elongated strip of UHMWPE. The UHMWPE strip 152 can be ofthickness of from about 1/16 to about ¼ inch. In one form the UHMWPEstrip 152 is about ⅛ inch in thickness.

In one form, each of the plurality of individual biasing members 136 arepositioned so as to overlap with an adjacent biasing member 136 tomaintain a substantially constant compressive force on the stalk.

In one form, biased guide assembly 134 is effective to accommodatestalks of diameters between about 1.5 to 3.0 inches.

Optionally, apparatus 100 may include a conveyer 160 for depositing cutrow crops thereupon. Conveyer 160 is operably connected to frame 112 forreceiving stalks and transferring them to a processing point P. Asshown, conveyor 160 runs along substantially the entire length of frame112.

Another saw or notching means (not shown) may be provided at or nearsecond end 126 of hollow arm 118. The notching means is provided toenable the notching of the stalk near its severed end to permit thehanging of the stalk for drying or curing, as is typically done withBurley tobacco.

In another form, a method of harvesting agricultural row crops havingstalks is provided. The method includes the steps of sequentiallyengaging stalks of row crops, cutting each sequentially engaged stalk soas to sever each stalk from the ground, applying a clamping force toeach of the engaged stalks sufficient to keep each stalk upright andconveying the stalks to a point for collection. The clamping force isapplied by a biased guide assembly for accommodating stalks of varieddiameters, the biased guide assembly comprising a plurality ofindividual biasing members positioned along at least a portion of ahollow arm to apply clamping force to the stalks as they are conveyedalong at least a portion of the hollow arm.

While the present inventions have been described in connection with anumber of exemplary forms, and implementations, the present inventionsare not so limited, but rather cover various modifications, andequivalent arrangements, which fall within the purview of the presentclaims.

1. An apparatus for harvesting agricultural row crops having stalks,comprising (a) a frame having a front portion and a rear portion, saidframe configured for traversing along a field of row crops; (b) a hollowarm mounted adjacent an upper section of said front portion of saidframe, said hollow arm comprising a first section disposed along anincline formed by said upper section of said front portion of said frameand the ground, said first section having a first end and a second end;(c) a stalk inlet positioned adjacent said first end of said firstsection of said hollow arm, said stalk inlet for receiving stalks of rowcrops; (d) means for cutting stalks of row crops, said means for cuttingstalks mounted within said first section of said hollow arm; (e) meansfor engaging and conveying the stalks along said hollow arm; and (f) abiased guide assembly for accommodating stalks of varied diameters, saidbiased guide assembly comprising a plurality of individual biasingmembers positioned along at least a portion of said hollow arm to applyan accommodating clamping force to the stalks sufficient to keep eachstalk substantially upright as they are conveyed along at least aportion of said hollow arm, said accommodating clamping forceaccommodating possible differences in stalk diameters from one stalk toanother.
 2. The apparatus of claim 1, wherein said means for engagingand conveying the stalks along said hollow arm comprises an endlesschain having a plurality of links, said plurality of links alternatelyprovided with at least one barb for engaging a stalk.
 3. The apparatusof claim 2, wherein said plurality of links are alternately providedwith three barbs for engaging a stalk.
 4. The apparatus of claim 2,wherein said endless chain is positioned to travel along at least aportion of a vertical wall of said hollow arm in a spaced relationshipwith said biased guide assembly.
 5. The apparatus of claim 1, whereinsaid inlet is provided in front of said means for cutting stalks andconfigured to direct the row crops into said means for cutting stalks.6. The apparatus of claim 1, wherein said means for cutting stalkscomprises a circular saw.
 7. The apparatus of claim 6, wherein saidcircular saw comprises a high speed tool steel blade.
 8. The apparatusof claim 6, wherein said circular saw comprises a carbide-tipped blade.9. The apparatus of claim 1, wherein at least a portion of saidplurality of individual biasing members include a friction-reducingpolymeric coating.
 10. The apparatus of claim 9, wherein saidfriction-reducing polymeric coating comprises ultra high molecularweight polyethylene.
 11. The apparatus of claim 1, wherein each of saidplurality of individual biasing members are positioned so as to overlapwith an adjacent biasing member to maintain a substantially constantcompressive force on the stalk.
 12. The apparatus of claim 1, whereinsaid biased guide assembly is effective to accommodate stalks ofdiameters between about 1.5 to 3.0 inches.
 13. The apparatus of claim 1,wherein said hollow arm further comprises a second section having afirst end and a second end, said first end operably connected to saidsecond end of said first section, said second section mounted along saidupper section of said front portion of said frame.
 14. The apparatus ofclaim 13, further comprising a conveyer for depositing cut row cropsthereupon.
 15. A method of harvesting agricultural row crops havingstalks, the method comprising: (a) sequentially engaging stalks of rowcrops; (b) cutting each sequentially engaged stalk so as to sever eachstalk from the ground; (c) applying a clamping force to each of theengaged stalks sufficient to keep each stalk upright; and (d) conveyingthe stalks to a point for collection, wherein the clamping force isapplied by a biased guide assembly for accommodating stalks of varieddiameters, the biased guide assembly comprising a plurality ofindividual biasing members positioned along at least a portion of ahollow arm to apply an accommodating clamping force to the stalks asthey are conveyed along at least a portion of said hollow arm, saidaccommodating clamping force accommodating possible differences in stalkdiameters from one stalk to another.
 16. The method of claim 15, whereinthe hollow arm includes a first section disposed along an incline formedby an upper section of a front portion of said frame and the ground,said first section having a first end and a second end and a an inletpositioned adjacent the first end of the first section of the hollowarm, the inlet for receiving stalks of row crops.
 17. The method ofclaim 16, wherein said engaging and conveying steps utilize an endlesschain having a plurality of links, the plurality of links alternatelyprovided with at least one barb for engaging a stalk.
 18. The method ofclaim 16, wherein the inlet is positioned in front of a means forcutting stalks and configured to direct the row crops into the means forcutting stalks.
 19. The method of claim 18, wherein the means forcutting stalks comprises a circular saw.
 20. The method of claim 15,wherein the biased guide assembly is effective to accommodate stalks ofdiameters between about 1.5 to 3.0 inches.